More than 3 million interactions around Australia’s Federal election were recorded across Facebook and Instagram on election day, 18 May. But it was the democracy sausage and not prospective prime ministers that proved most popular in discussions.

The new feature explains how a person's past interactions impact the ranking of posts in their news feed, allowing users to see why they're seeing a certain post from a friend, group, or page that they are following in their news feed.

"Faces are just like fingerprints, we do not have the exact same face in the total population of the world, so this data that is being gathered can be used to connect to particular interests that this audience has."

In 2010, when Kevin Systrom was building an also-ran social check-in service called ‘Burbn’, he decided to take a break and travelled to a beach town in Mexico with his then-girlfriend Nicole. It is here that Nicole – owner of the feet in the picture above and also a...